Method and apparatus for detonating combustible substances at atmospheric pressure

ABSTRACT

In a method of exploding a gaseous combustible substance of atmospheric pressure, said substance is charged together with air to a combustion chamber provided with controllable ignition means. Finely divided particles of an explosive substance are also charged to the combustion chamber, the size of the particles being such as to enable them to be suspended in the combustible substance-air mixture. The resulting mixture of explosive particles, combustible substance and air is then ignited. The amount of explosive particles charged to the combustion chamber can be regulated so as to control the rate of combustion of the gaseous mixture.

United States Patent 1191 Arvidsson METHOD AND APPARATUS FOR DETONATINGCOMBUSTIBLE SUBSTANCES AT ATMOSPHERIC PRESSURE 1 1 Nov. 11, 19753228.191 1/1966 Zeman fill/39.82 E

Primary E.\aminer-Edward G. Favors Attorney, Agent. or Firm-Eric Y.Munson [57] ABSTRACT In a method of exploding a gaseous combustible substance of atmospheric pressure. said substance is charged together withair to a combustion chamber provided with controllable ignition means.Finely divided particles of an explosive substance are also charged tothe combustion chamber the size of the particles being such as to enablethem to be suspended in the combustible substance-air mixture. Theresulting mixture of explosive particles. combustible substance and airis then ignited. The amount of explosive particles charged to thecombustion chamber can be regulated so as to control the rate ofcombustion of the gaseous mixture.

11 Claims, 7 Drawing Figures Sheet 1 of 2 3,918,879

U.S. Patent Nov. 11, 1975 US. Patent Nov.11, 1975 Sheet20f2 3,918,879

METHOD AND APPARATUS FOR DETONATING COMBUSTIBLE SUBSTANCES ATATMOSPHERIC PRESSURE FIELD OF THE INVENTION The present inventionrelates to a method of exploding or detonating combustible substances atatmospheric pressure and an apparatus for putting the method intoeffect.

DESCRIPTION OF THE PRIOR ART It is generally known that althoughhydrocarbons such as propene, propylene, butane, acetylene and the likeare relatively inexpensive in relation their energy content, their usein practice is restricted because of their low rate of combustion. Ithas been established that when combusting the aforementionedhydrocarbons at atmospheric pressure, there is obtained an adiabaticpressure increase of the order of magnitude of 7 atm. it has also beenestablished that when hydrocarbons are ignited in a certain manner, inan especially designed combustion chamber, it is possible to obtainworking pressures which are many times greater that that aforementioned.In this latter respect, it has been necessary to initiate the combustionprocess by means of an electric shock or a laser beam of significantenergy content. With such combustion processes it must be ensured thatthe quantity of gas located nearest the spark and combusted in the firststage of said combustion process, creates a pressure of such magnitudeas to change the combustion conditions for adjacent gas particles. Itwill be gathered from this that the immediately adjacent gas particlesare combusted in a microenvironment which differs in respect of pressureand temperature from the total environment which existed in thecombustion chamber prior to the ignition of said hydrocarbons.Previously, the problems associated with the task of obtaining aconsiderable increase in the combustion rate of hydrocarbons, andtherewith in the exploding or detonating force, have been difficult byresolved.

OBJECTS OF THE PRESENT INVENTION It is an object of this invention toprovide ways and means whereby a combustible substance, such as gas orgaseous mixture can be detonated at atmospheric pressure so that thecombustion rate of said substance and the energy produced therewith canbe controlled. By charging a combustible substance together with oxygen,preferably atmospheric oxygen, into a combustion chamber and, at thesame time, charging to said chamber particles of a material, which, incombination with said combustible substance, is capable of causing adetonation, it is possible to select the rate of the mixture in saidchamber and the energy produced thereby can be controlled by appropriateselection of the components of said mixture. The ignition of thecombustible substance together with the particles admixed therewith iseffected via a low-energy ignition device. The size of the explosiveparticles mixed with the combustible substance to facilitate thecombustion thereof is preferably such as to enable said particles to besuspended in said substance. The particles shall also have a high rateof combustion.

In accordance with one aspect of the invention the aforementionedparticles may comprise particles of an explosive substance, and it willreadily be perceived that the quantity of particles charged to thecombustible substance may be varied so that the combustion rate of saidsubstance can be controlled and so that the forces resulting from thedetonation can be controlled.

The invention also relates to apparatus for exploding or detonating acombustible substance, such as gas or a gaseous mixture, at atmosphericpressure.

BRIEF DESCRIPTION OF THE DRAWINGS So that the invention will be morereadily understood and further features thereof made apparent apreferred embodiment of the invention will now be described withreference to the accompanying drawing, in which FIG. la illustratesdiagramatically an apparatus for detonating a combustible gaseoussubstance at atmospheric pressure,

FIG. lb shows in larger scale an element of the apparatus of FIG. la,

FIG. 2a shows diagramatically a first particle transporting means in theform of an ampule,

FIG. 2b is another view of the ampule shown in FIG.

FIG. 3 shows a second particle transport means in the form of a tube,

FIG. 4a shows part of a transport and separating device for the ampuletype particle transport means shown in FIGS. 20 and 2b, and

DESCRIPTION OF THE PREFERRED EMBODIMENT.

FIG. 1a shows diagramatically an embodiment of an apparatus with which acombustible gaseous substance can be exploded or detonated atatmospheric pressure, said apparatus comprising a combustion chamber 1in which said substance is detonated or exploded. With the illustratedembodiment, the chamber 1 comprises an inverted double-walled box-likestructure, the vertical inner walls 1b of said structure being spacedfrom the outer walls lb thereof. This box like structure is intended torest on a supporting surface la and contained within the respectivewalls of said structure 1 is a liquid, as shown at 1c. Connected to thechamber 1 is an inlet pipe 2 having a valve a incorporated therein. Thevalve a facilitates the supply of a combustible gaseous substance to thechamber 1 in which chamber the gaseous substance is admixed withparticles of an explosive substance, as hereinafter described.

To eliminate the risk of unintentional exploding or detonation of theparticles of explosive substance, said particles are preferablypre-packed to form a string 13 which is wound on a drum or the like 12.The chamber 1 also communicates with a pipe 3, through which waste gasescan be evacuated from the chamber. The reference numeral 4 illustratesan ignition device adapted to create a spark in the chamber 1 for aninitial ignition of the gaseous substance, said spark being ofsufficient strength merely to ignite that portion of the gaseoussubstance located adjacent the spark gap of the sparking device, thisportion of the gaseous substance in turn igniting immediately adjacentportions of said substance, which as a result on their rapid explodationor detonation-like process of combustion in combination with particlesof explosive substances admixed therewith cause the wave to propagate torespective adjacent portions of said gaseous substance. The ignitiondevice does not form part of the present invention and any appropriate,conventional ignition device may be used with the apparatus of theinvention. The ignition device used may be one with which theexplodation or detonation process can be initiated automatically in thechamber 1 by means of a program-controlled mechanism. The device mayalso be a manually controlled device. The combustible gaseous substance,which as before-mentioned may comprise hydrocarbons, is lo cated in agas container 5, from which said substance is fed through a pipe 6, viaa pipe 5a and a valve g. Oxygen, for example atmospheric oxygen, issupplied to the apparatus via a line 7, to which is connected a valve f,the line 7 being connected to the pipe 6 upstream of the valve g. Theapparatus may be placed under a pressure below atmospheric or under apressure below the prevailing ambient pressure via a pipe 8, which isalso connected to the pipe 6 and which has a valve e associatedtherewith. As beforementioned the particles of explosive substance arepreferably packed in transport packages to prevent unintentionaldetonation thereof. Before being charged to the chamber 1, however, theparticles are released from said packages, as hereinafter described. Aswill be seen from FIG. 1a, the conduit 2 has a portion which in theposition of use of the apparatus, forms a preferably verticallyextending space 9 in which the particles of explosive substance,subsequent to being released from said packages, are able to fall and becollected in a curved portion 2a of said conduit 2. As seen in thedrawing, there is located above the space 9 a feed chamber 10, which isseparated from the space 9 via a valve c and which is sealed from theambient pressure by a valve d incorporated in the pipe 6.

The particles of explosive substance are packed in unit packages, whichare supplied to the apparatus in the form of a string of such packages.As before-mentioned, the packages may have the form shown in FIGS. 20,2b or 3. Which ever form the package has, however, said packages shallbe joined together to form said continuous string 13. The drum 12 onwhich the string 13 is wound comprises a rotatable magazine, from whichthe string 13 may be conveyed through a passage 13a to a package unittransporting and separating device 14.

The particle packages or ampules shown in FIG. 2a and 2b comprise twohollow halves 16, 17, in the interior of which particles 18 of anexplosive substance are stored. With the illustrated ampule, theparticles are enclosed between two mutually parallel loosely arrangedplates 19, 20, each of which defines one side of two air spaces 21, 22.In the string 13, the ampules are loosely enclosed between two stringhalves 28a and dab, the string halv 28b being omitted in FIG. 2a for thesake of clarity. The string halves may have the form of doubleCellophane layers provided with bulges in the form of halv ampules andare arranged to release the ampules at the device 14 so that, as shownin FIG. Ia, said ampules are able to fall from said device 14 through asafe-fall distance 11, down into a funnel 15, valve 12 which is locatedupstream of funnel 15 being open. The ampules are then fed through thefeed chamber 10, whereafter the valve b is closed. The valve e in pipe 8and the valve d in pipe 6 are then opened, to lower the pressure inspace 9, whereafter said valves are reclosed. It is assumed that duringthis latter sequence the valve a is closed. Valve c is then opened, topermit an ampule to fall down into the space 9 and, as a result of thesubpressure prevailing in said space, the air enclosed in spaces 21 and22 of the ampule will expand, causing the two halves I6, 17 to separatefrom each other,

whereupon the loose plates 19, 20 will act as plungers to release theenclosed particles 18, so that said particles fall through the space 19to be caught in the bend 2a of the conduit 2. The gaseous combustiblesubstance is then passed to the space 9 from the gas container 5, viathe pipe 6, and oxygen which may be in the form of atmospheric oxygen,is fed from a source not shown to the pipe 7 located downstream of thecontainer 5, the gaseous mixture forcing the particles of explosivesubstance into the chamber 1, via the conduit 2 and the valves a.

An alternative embodiment of the particle transporting package unit isshown in FIG. 3. The particles, here identified by the reference 23, areenclosed in a tubular package which is compressed at predeterminedsections therealong to form mutually coherent portions A, B, C, each ofsaid portions having the same form and the same volumetric capacity. Theportion A is sealed at its upper and lower ends Al and A2 resp. andcontains as gas, such as air for example. The portion B contains a unitquantity of explosive particles 23 and, similarly to portion A, issealed at its respective upper and lower ends B1 and B2. The portion Cmay be caused to serve as a pre-load chamber and may be provided with anopening 24 at one side thereof through which the particles may be fedinto the package unit. The portion C may also be provided with aso-called tear line 25, which is intended to facilitate severing of thepackage unit when charging the same prior to the detonation sequence.The portion C may include volatile liquid. The portions A, B and C aremade from a continuous tube and in this way form a string of units withequal division between the sealed ends thereof. As will be readilyunderstood, all of said portions may be filled with explosive particles23. The tube preferably comprises a flexible material, such as asynthetic resin or aluminium and may be coiled on a roller, such asroller 12 in FIG. la. The package unit transporting and separatingdevice 14 shown in FIGS. 1a and 1b is suitable for separating packageunits of the type shown in FIG. 3 and comprises a peg wheel 29, thespacing between the pegs being the same as the spacing between thenarrow sealed ends of the tubular package unit shown in FIG. 3. Thewheel 29 is arranged for rotation around a shaft 29a. Co-acting with theshaft 29a is a transmission device (not shown in Fig. 1a) which isarranged to co-act with a wheel 30, which is arranged for rotation abouta shaft 300. The wheel 30 is provided with one or more knives 31 whichare so guided that they are activated at each third spacing unit of thepeg wheel, thereby to separate the package units A and B and C. As willbe readily understood, the knives may also be arranged to sever eachindividual package unit, when each package unit contains explosiveparticles. FIG. lb shows in larger scale the peg wheel 29 withassociated pegs 29b and the package unit A, B and C shown in FIG. 3. Aswill be seen, the packages separated by the knives 31 will fall downinto the funnel 15, through the safe-fall distance 11.

In FIGS. 40 and 4b there is shown a package unit transporting andseparating device 14 which is especially adapted to feed package unitsof the type illustrated in FIGS. 2a and 2b. To this end the device isprovided with two wheels 26a and 26b. Each wheel has four cogs ofmutually equal division corresponding to the distance between adjacentampules in the string 13. The string 13 is advanced via guide rollers40a and 40b,

. which are adapted to orient the string 13 in relation to the wheels26a and 26b. The string portions 28a and 28b are bent off and accompanythe rotation of said wheels 26a and 26b. The wheels 41a and 41b arebiased against the wheels 26a and 26b and as a result of thisarrangement the ampules containing explosive substance, shown in H0. 4aand 4b by the reference numeral 18, will be released from the string 13in space 27, whereupon the explosive substance 18 will fall down intothe funnel 15.

FIG. 4b shows in larger scale a number of the elements shown in FIG. 4a.

If it is now assumed that the package units shown in FIG. 3 fall intothe space 9 in the conduit 2 at the same moment as the valve e and d areopened, the air contained in said units will expand to rupture saidunits, thereby allowing the particles in portion B of the package unitto fall into the curved portion 2a of the conduit 2. If desired, theparticles in the portion B of said package unit may be in paste form,i.e. a mixture of a volatile liquid and particles. in this instance, thepaste will pass through the constrictions present between adjacentpackage units at the lower portion of the package unit portion B, asshown at 32, in the form of a continuous string. This string is sobrittle, however, that it is readily broken up upon falling into thecurved portion 2a of the conduit 2. The volatile component of the pasterapidly evaporates, leaving the particles relatively dry.

The valve d downstream of the feed chamber is then closed in a knownmanner, whereafter air and a gaseous substance, for example gasol orpropylene is supplied from the containers 5 and 7 respectively in adetermined mixing ratio, e.g. 1:22.

The mixture ratio between the gaseous substance and oxygen such asatmospheric oxygen, can be selected in accordance with the desireddetonation effect.

As previously mentioned, the valve a may conveniently be opened at thesame time as valves g and f are opened, these latter valves being openedto give the mixture a predetermined air to gaseous substancerelationship. The particles present in the space 9 will then beentrained with the gas flow into the chamber 1, in which they are finelydispersed and suspended in said chamber until the explosive ordetonation process takes place. Exploitation or detonation of themixture in the chamber 1 is initiated by an electric spark, generated bythe ignition device The time at which the explosive or detonationprocess is initiated may be controlled by a programmed device. ln thiscase, the process is controlled preferably automatically although incertain instances it may be more suitably to control said processmanually.

The chamber 1 may have the form of an inverted box resting on the bottomof a liquid-filled vessel, or any other suitable form adapted toindustrial requirements when it is required to compress and/or deformmaterial by explosion techniques and for such processes as those whichrequire a large energy output and a short explosive or detonation time.Examples of such processes include the instantantous compression ofporous materials, such as wood for example, in conjunction with woodimpregnation process, or deformation processes carried out within themicroplastics industry.

The apparatus illustrated in the drawings has the following mode ofoperation:

A string of package units containing explosive particles 23, 18, is fedfrom the reel 12 to the package unit separating device 14, thearrangement being such that the severed units fall into the funnel 15.The packages fall from the funnel 15 into the space 9, which may beplaced under a pressure below the prevailing ambient pressure, whereupona combustible gaseous substance is fed from the gas container 5 to thespace 9 together with oxygen to cause the exploxive particles to movealong the conduit 2, through valve a into the chamber 1. The particlesare of such size that they are maintained suspended in theaforementioned combustible substance and the resultant mixture ofexplosive particles and combustible substances is ignited by means ofthe ignition device 4.

Because the explosive particles are encased in their respective packageunits prior to leaving the space 9, there is less risk of unintentionalexplosion or detonation of said particles due to extraneous sources.

As previously mentioned, the processes may be controlled by programmedmechanism located at a central operation station, as may also theduration of each process, together with the time interval betweensuccessive explosions or detonations. The valves and devices em ployedduring the chamber charging and process may be electrically orhydraulically controlled.

The invention is not restricted to the embodiments described andillustrated but may be modified within the scope of the followingclaims.

The explosive particles may comprise a single explosive substance or maycomprise a number of explosive substances. For example the particles maycomprise percent nitroglycerine in 25 percent kieselguhr, aluminiumpowder or the like.

The used explosive substance may be of the primary and/or secondarytype. It is suggested to use penta erytritol tetra nitrat having aparticle size or fineness of grain within the range 0.03-0.01 mm,aluminium pow der within the range 10-20 m or magnesium powder withinthe range 5-10 m. It is known that powder with a size within the lowerrange is causing a higher detonation velocity than powder with largersize.

The initiation of the mixture may be caused by an electric spark, heatedsurfaces or laser beam. When using an electric spark it is suitable tohave the electrodes on a distance exceeding 0.2 mm. The minimum energymay in a propane-oxygen-nitrogen gas mixture be about 0.002 mi. Othermixtures will need other values in the minimum energy consumption.

In the description used expression expl0sion" is meant that the velocityof the burning is lower than that of the sound and the used expressiondetonation" is meant that the velocity of the burning is higher thanthat of the sound. By using this invention it is a desire to haveexplosion with a high velocity of the burning and may therefor be closeto the detonation.

1 claim:

1. A method for exploding or detonating a combustible gaseous substanceat atmosphere pressure comprismg a. charging to an combustion chambercombustion ingredients consisting of al. a combustible gaseoussubstance,

a2. oxygen, preferably in the form of air,

a3. particles of an explosion substance,

b. obtaining a mixture of said ingredients in said chamber, and

c. igniting said mixture to explode or detonate the same.

2. A method for exploding or detonating a combustible gaseous substanceat atmospheric pressure, comprising packaging determined quantities ofexplosive particles in unit packages, feeding said packages to a vacuumchamber. placing said chamber under a pressure below the prevailingambient pressure thereby to release said particles from said packages,feeding to said chamber a combustible gaseous substance and oxygen,preferably in the form of air in a determined substance-to-air ratio,causing said substance, said oxygen and said explosive particles to passinto said combustion chamber to provide a mixture therein, and ignitingsaid mixture to explode or detonate the same.

3. A method according to claim 1, wherein the size of said explosiveparticles is such as to enable said particles to be suspended in saidgaseous combustible substance and oxygen, preferably in the form or air.

4. An apparatus for exploding or detonating a combustible substance atatmospheric pressure, comprising:

a. an combustion chamber,

b. a source of gaseous, explosive substance,

c. an oxygen source,

(1. a source of explosive particles,

e. means for charging to said combustion chamber said gaseous substance,said oxygen and said explosive particles to form a mixture therein, and

f. means for exploding said mixture in said combustion chamber.

5. An apparatus according to claim 4, wherein said source of explosiveparticles comprises a plurality of rupturable explosive particle unitpackages.

6. An apparatus according to claim 4, wherein said rupturable unitpackages are in the form of coherent strings of packages, and whereinmeans are provided for serving said strings to form separate unitpackages.

7. An apparatus according to claim 4, wherein means are provided toreceive unit packages so as to rupture the same, said means beingconnected to said oxygen source and said explosive substance source.

8. An apparatus according to claim 7, wherein said unit packagereceiving means has the form of a vacuum chamber,

9. An apparatus according to claim 4, wherein said explosive substancesource and said oxygen source communicate with a common supply pipe, andwherein valve means are provided to regulate the feed of said substanceand said air to said supply pipe.

10. An apparatus according to calim 6, wherein said severing means hasthe form of a rotatable wheel provided with string serving means spacedat determined distances apart.

11. An apparatus according to claim 4, wherein the means for explodingsaid mixture is connected to a programmed explosion sequence initiatingdevice.

1. A METHOD FOR EXPLODING OR DETONATING A COMBUSTIBLE GASEOUS SUBSTRATEAT ATMOSPHERE PRESSURE COMPRISING A. CHARGING TO AN COMBUSTION CHAMBERCOMBUSTION INGREDIENTS CONSISTING OF A1. A COMBUSTIBLE GASEOUSSUBSTANCE, A2. OXYGEN. PREFERABLY IN THE FORM OF AIR, A3. PARTICLES OFAN EXPLOSION SUBSTANCE, B. OBTAINING A MIXTURE OF SAID INGREDIENTS INSAID CHAMBER, C. IGNITING SAID MIXTURE TO EXPLODE OR DETONATE THE SAME.2. A method for exploding or detonating a combustible gaseous substanceat atmospheric pressure, comprising packaging determined quantities ofexplosive particles in unit packages, feeding said packages to a vacuumchamber, placing said chamber under a pressure below the prevailingambient pressure thereby to release said particles from said packages,feeding to said chamber a combustible gaseous substance and oxygen,preferably in the form of air in a determined substance-to-air ratio,causing said substance, said oxygen and said explosive particles to passinto said combustion chamber to provide a mixture therein, and ignitingsaid mixture to explode or detonate the same.
 3. A method according toclaim 1, wherein the size of said explosive particles is such as toenable said particles to be suspended in said gaseous combustiblesubstance and oxygen, preferably in the form or air.
 4. An apparatus forexploding or detonating a combustible substance at atmospheric pressure,comprising: a. an combustion chamber, b. a source of gaseous, explosivesubstance, c. an oxygen source, d. a source of explosive particles, e.means for charging to said combustion chamber said gaseous substance,said oxygen and said explosive particles to form a mixture therein, andf. means for exploding said mixture in said combustion chamber.
 5. Anapparatus according to claim 4, wherein said source of explosiveparticles comprises a plurality of rupturable explosive particle unitpackages.
 6. An apparatus according to claim 4, wherein said rupturableunit packages are in the form of coherent strings of packages, andwherein means are provided for serving said strings to form separateunit packages.
 7. An apparatus according to claim 4, wherein means areprovided to receive unit packages so as to rupture the same, said meansbeing connected to said oxygen source and said explosive substancesource.
 8. An apparatus according to claim 7, wherein said unit packagereceiving means has the form of a vacuum chamber.,
 9. An apparatusaccording to claim 4, wherein said explosive substance source and saidoxygen source communicate with a common supply pipe, and wherein valvemeans are provided to regulate the feed of said substance and said airto said supply pipe.
 10. An apparatus according to calim 6, wherein saidsevering means has the form of a rotatable wheel provided with stringserving means spaced at determined distances apart.
 11. An apparatusaccording to claim 4, wherein the means for exploding said mixture isconnected to a programmed explosion sequence initiating device.